Re: So here it is one year later...

On Fri, 28 Jan 2005, Dean Anderson wrote:

> >   ((3.7259 / 100) * 54725) = 2038.998775
> > 
> > I'd suspect that rounding error means that 2039 spam messages passed the
> > SPF check, so round to 2039.
> > 
> >   ((18.9072 / 100) * 6680) = 1263.00096
> > 
> > and 1263 hams passed SPF.  Total those, and you get 3302 messages
> > from the overall corpus passing SPF; to express that as a percentage
> > of the total overall corpus, in other words "OVERALL%", you compute
> > (3302 / 61405) * 100 = 5.377.

BTW, I'd say that 38% of the SPF use was ham, and 62% was spam.
    1263 ham / 3302  = ~38%
    2039 spam / 3302 = ~62%

So, 24% versus the 34% in September.  Either slightly better than
September, or perhaps the sample is too small and skewed to be useful. Or 
both.  Its still better to block whenever you see SPF.

Still, I'd think the 3.7% of total spam using SPF is still fairly
significant, and probably reflects the relative proportion of genuine
commercial spam to non-commercial spam.  It would be interesting to know,
of those spams that pass SPF, how many are CAN-SPAM compliant?  How many
of the non-SPF spams were CAN-SPAM compliant?  I'd conjecture a strong
correlation.

		--Dean

-- 
Av8 Internet   Prepared to pay a premium for better service?
www.av8.net         faster, more reliable, better service
617 344 9000